How to use the smartpointer overloads inside `<span_ext>`?

[Dmitry Kobets]

There are two overloads for gsl::make_span which take a Ptr that has an element_type class member. Presumably this was introduced to handle smartpointers. However, since gsl::span itself doesn't have a way to construct a span from a smartpointer, and there is no implicit conversion from a STL smartpointer to a raw pointer, the following code doesn't compile anyways with the current implementation:

#include <gsl/span>
#include <memory>

int main()
{
    std::unique_ptr<int> a(new int(42));
    gsl::span<int> s = gsl::make_span(a);
}

The two overloads in <span_ext>:

template <class Ptr>
constexpr span<typename Ptr::element_type> make_span(Ptr& cont, std::size_t count)
{
    return span<typename Ptr::element_type>(cont, count);
}

template <class Ptr>
constexpr span<typename Ptr::element_type> make_span(Ptr& cont)
{
    return span<typename Ptr::element_type>(cont);
}

[Herb Sutter]

Editors call: Deprecate these functions.